timer

Hi guys
I m want to build a timer that runs for 15 minutes and then goes off,
Any suggestion
type of timer ?
Is it easier to use a PIC ?
thanks

A U6046 or U6047 8 pin dil IC designed for automotive applications such as heated screen timing can produce time delays of 3.7 sec to 20 hours, designed for 12v operation and can switch 300mA. Only problem may be the 1.3mA typical supply current if running from batteries.

When switched on by an 'on' contact it will switch off by either an 'off' contact or when the time delay expires - needs 3 resistors + 2 capacitors.

Datasheet available at:-

http://pdf1.alldatasheet.com/datasheet-pdf/view/90384/TEMIC/U6047B.html

Steve.

What starts the timer?
What does the timer do or control when on.
What does the timer do or control when off.
What is your power source.
Does the timer need to be powered and waiting, or dead, when off?

The devil's in the details.

Ken

PIC's are evil, there not real electronics. use a 555 I.C. in monostable.

if you change the values of the 2 compovents what go to pins 6 and 7 the time constant will change

This is what i want to achieves
I want my timer to obstruct the mains power for 15 minutes then go dead.
After 15 minutes there will be a normal connection between the mains and my module.
Next time the timer will be on is when the power is on again after a power faillure.

What starts the timer?
Mains voltage but i will use a power supply to supply the PIc or 555
What does the timer do or control when on.
The timer when on control ..the mains voltage ( it has to hold for 15 minutes then release it )

Thank you guys for your help ..i hope that extra details that i gave above will help you to have a picture of what i want to achieve .

What does the timer do or control when off.
Does the timer need to be powered and waiting, or dead, when off?
I need my timer to be active only for 15 minutes and wait for the next cycle of mains faillure / power on again

The devil's in the details.

Ken

Sounds like you're attempting to protect an A/C compressor and/or refridgerator/freezer compressor from stalling/overheat when the power is cycled rapidly.

The former will require monkeying around in the mains panel if the A/C compressor is a permanently installed unit. This is best left up to a licensed electrician.

Good answers!..now: what is the mains voltage and how much current will the switch need to carry when reconnecting the mains?

Ken

Thanks again guys,
My last question is this, my main concern is ..Is it possible to deactivate the timer ..because if i use a timer ( monostable) mode the delay will come back again and again ..it will never stop until a power faillure
Is it possible to make the timer just go dead after the 15 minutes ...
I think it s possible to do with A PIC but frankly i don t realy know the circuit may look like if i use a timer

If this is just a matter of keeping power away from the load for fifteen minutes after an outage, try using a "time-delay relay."

http://documents.tycoelectronics.co...chrtrv&DocNm=1308242_CG&DocType=DS&DocLang=EN

Thingmaker 3

I had a look at the prices of that timer ...god is too expensive

Omar, there are lot's of Delay-on-Make modules in the $30 to $50 range. Here are some manufacturers the I found while looking for Delay-on-Break modules. These are available through venders like Mouser, Allied, Newark...

Ken

http://www.artisancontrols.com/
http://www.ssac.com/
http://www.accesscontrolsales.com/
http://www.airotronics.com/
http://www.icmcontrols.com/products

Comment: Most of thes timers handle only about 1A, so if you need to control more current you will also need an electromechanical or solid steate relay.